Experimental Evaluation of Steel-Plate Composite Walls Subject to Blast Loads

Steel-plate composite (SC) walls consist of a concrete infill sandwiched between two steel faceplates. The faceplates are anchored to the concrete using stud anchors or ties, and connected to each other using steel tie bars. This type of sandwich composite construction has the potential for excellent blast resistance because the steel faceplates provide confinement to the concrete and prevent concrete scabbing and spalling. This paper presents the results of an experimental investigation conducted to evaluate the blast resistance of small-scale SC wall panel specimens by subjecting them to short-duration uniform pressure loads in a blast load simulator facility. All the panel specimens had the same global dimensions (length = 1,626 mm, width = 279 mm, and thickness = 102 mm) but varied certain design parameters: (1) the faceplate reinforcement ratio ($\rho =2\times$ faceplate thickness/wall thickness = 3.5–5.6%), (2) faceplate slenderness ratio ($\lambda$ = stud anchor spacing/plate thickness = 18–29), (3) faceplate yield strength ($F_y=400–700\mathrm{MPa}$), and (4) tie reinforcement ratio (${\rho }_t$ = area of tie bar/square of tie spacing = 0.37–1.23%). The blast load peak reflected pressures varied from 130 to 425 kPa, and the corresponding reflected impulses varied from 1,790 to $7,650\mathrm{kPa}·\mathrm{ms}$. This paper summarizes the experimental results including (1) the dynamic displacement history at two locations, (2) acceleration history at midspan, and (3) strain histories at several locations on the steel faceplates. The reflected pressures were also recorded, and high-speed videography from three directions was used to record the response. Experimental results indicate that the structural responses of all 12 panel specimens included elastic and plastic deformations and were dominated by flexural behavior. Experimental results were compared with analytical results from a single-degree-of-freedom (SDOF) model. The SDOF model estimated displacements on average 10% larger than measured, indicating that one-way behavior of SC walls subjected to short-duration uniform pressure loads is reasonably estimated using fundamental bending mechanics.